A scene in the new food-revolution documentary called Forks Over Knives finds firefighter Rip Esselstyn climbing up a firehouse pole and chanting: “Real men eat plants; real men eat plants.”

The affable health buff is not just the son of one of the film’s two key researchers, heart specialist Caldwell Esselstyn Jr., but also a poster boy for the plant-based, whole-foods diet his father espouses. A onetime competitive swimmer and pro triathlete, he’s living proof that you don’t need meat—or dairy-derived protein—to do major sports and that giving up that protein won’t turn you into the stereotypical emaciated weakling. And as he recounts in the film, he was able to get his entire firehouse in Austin, Texas, to adopt the diet that the new film argues can all but eradicate heart disease and cancer.

Still, it wasn’t always this way. Before his father’s groundbreaking research in the early ’80s, Esselstyn chowed down like the majority of the population. “I grew up in a house where we ate everything under the sun: candy, peanut-butter-and-jelly sandwiches, BLTs, pot roasts, steaks, pizza, burgers, French fries. We’d go to McDonald’s and Burger King, and we ate ice cream galore,” Esselstyn, the author of the guide-cookbook The Engine 2 Diet, tells the Straight on the phone from his Texas home. But in 1987, as his father was accumulating overwhelming evidence that a plant-based diet could not only prevent but even reverse heart disease, he decided to give up meat products and processed foods.

Forks Over Knives piles up the scientific evidence, much of it decades old, to support Esselstyn’s claims. But the message has never gotten out to the public, and Esselstyn feels that the documentary (which opens here Friday [May 20] at the Cineplex Odeon International Village) could power a food revolution already started by movies like Super Size Me and Food, Inc. And yet millions of people remain unaware that study after study shows populations that have introduced meat and dairy into their diets see their heart disease and cancer rates jump.

“On a mass scale, we’ve been duped and bamboozled to believe that you need to get protein from animals and that you need three servings of dairy a day because it ”˜does a body good’. They spend close to $180 million a year trying to whitewash us. So it’s an uphill battle.”

Esselstyn feels passionate about the subject, and not just because his father spearheaded the research. He tells the Straight that as a fireman, he has to respond to more and more emergency calls from people with heart ailments, diabetes, and obesity. With his book, his job promoting the diet at Whole Foods Markets, and now Forks Over Knives, he says he hopes to “hold people’s hands” in their efforts to change their diet.

His final advice on the subject to anyone looking to give it a try?

“The best way to do this is not to take baby steps,” he says. “I tell people to take a 28-day challenge and see all the transitional things that take place in your body, and then you decide after that.

“You can do this. If a firehouse in Austin, Texas—a bunch of doughnut-loving, oil-drizzing, meat-eating firefighters—can do this, then anyone in North America can.”

Watch the trailer for Forks Over Knives.